Seeking help with NLL-SSST-coherence

[10go-L]

Hello Anthony,

I'm currently working with three stations and have been encountering that the len3 error in the ./NLL/loc_s/ALL.sum.grid0.loc.hyp file is around 30km. Given this, I'm interested in using NLL-SSST-coherence to potentially improve the earthquake location accuracy.

I would greatly appreciate any guidance or suggestions on how to effectively use NLL-SSST-coherence. I don't know how to start.

Thank you in advance for your assistance!

Best regards,
D

[alomax]

Hello D,

I am not sure if NLL-SSST-coherence will help much if there are only 3 stations (6 P and S picks maximum per event?), as the NLL-SSST-coherence procedure depends on good spatial coverage and distribution of the stations and seismicity (as well as a large number of events) to accumulate information about the picks and residuals and improve location quality.

I can take a quick look at your standard NLL configuration to see if there may be ways to improve those locations.

Otherwise, to get started with NLL-SSST-coherence, best to look at the papers:
https://doi.org/10.1029/2021JB023190
https://seismica.library.mcgill.ca/article/view/324
and the example application for Parkfield:
https://zenodo.org/record/7944033

I hope this helps,
Best regards,
Anthony

[10go-L]

Thank you for the quick response, Anthony.

I had hoped that NLL-SSST-coherence might offer some improvement, but I understand the limitations given the number of stations. It's been challenging to enhance the locations, and I even tried hypoDD, but the results were not favorable. I've attached the configuration files for your reference.

NLL_master.txt
NLL_master_s.txt

Thanks again for your guidance and I appreciate any comments you have on those.

Best regards,
D